Reliability of NPT scoring and visual estimates of erectile fullness

We report the reliability of nocturnal penile tumescence (NPT) scoring and visual estimates of erectile fullness performed by a group of eight registered polysomnographic technologists (RPSGTs). We achieved overall good to excellent interrater reliability (as measured by coefficients of variation, CVs) for seven widely used electrographic measures of NPT activity: number of episodes, categorization of episodes (full or partial), total tumescence changes, tip change, base change, duration of episode, and duration of 80% maximum tumescence. In two different visual estimate trials using photographs, separated by 2 weeks, female technologists (n = 4) made mean visual estimates of erectile fullness that were significantly higher than those of male technologists (n = 4). In addition, the CVs among the female technologists on visual estimates was consistently lower than those of the males. Higher correlations, however, were found between male technologists' estimates of fullness versus buckling force than for female technologists' estimates. Thus, the gender of a technologist may affect visual estimates of erectile fullness during NPT assessment.